British Rail Class 306
| refurbishment = 1960-1961 | numberbuilt = 92 trainsets | formation = + + }} | diagram = | code = AM6 | fleetnumbers = }} | capacity = | operator = British Rail | depots = Ilford | lines = Shenfield Line | carbody = | trainlength = | carlength = (DMSO) | (TBSO)| (DTSO) }} | width = | height = | floorheight = | platformheight = | entrylevelorstep = | doors = Bi-parting sliding | art-sections = 3 | wheeldiameter = | wheelbase = | maxspeed = | weight = (total)| (DMSO)| (TBSO)| (DTSO)}} | traction motors = 4 × EE 504 | poweroutput = 4 × | electricsystem = | collectionmethod = Pantograph | uicclass = Bo'Bo'+2'2'+2'2' | aarwheels = | bogies = Thompson | brakes = Air (EP/Auto) | safety = | coupling = Screw | multipleworking = Within class | light = | gauge = | notes = }} The British Rail Class 306 was a type of electric multiple unit (EMU) introduced in 1949. It consisted of 92 three-car trains which were used on newly electrified suburban lines between and London Liverpool Street. Overview Class 306 trains were built to a pre-World War II LNER design by Metro Cammell and Birmingham RCW, and were equipped with English Electric traction equipment. Each carriage featured two sets of twin air-operated sliding passenger doors, which could be opened by either the guard or the passengers using the passenger operated buttons fitted next to them, on both the outside and inside of the trains. When first built the trains were energised at 1,500 V direct current (DC) which was sourced from overhead wires, being collected by a diamond pantograph located above the cab on the Motor Brake Second Open (MBSO) vehicle. In the early 1960s the overhead wires were re-energised at 25,000 V alternating current (AC) (and 6,250 V AC in the London area) and the trains were rebuilt to operate using this very different electrical system. This entailed the fitting of a transformer and rectifier unit, which were located on the underframe between the bogies of the intermediate carriage. At the same time the location of the pantograph was moved to this carriage as well. Because this reduced the headroom inside the train, the guards' compartment was relocated to be directly below the pantograph, which was replaced by the more modern Stone Faiveley AMBR pantograph design. The trains were then re-numbered 001-092 with the last two digits of each carriage number (previously numbered in the LNER coaching series) the same as the unit number. Withdrawal and preservation The Class 306 trains were withdrawn in the early 1980s, and one unit, 306017, has been preserved. It has been repainted in a near original green livery, albeit with a yellow warning panel on the front to comply with present-day safety regulations. The 306 unit was in store at MoD Kineton awaiting the resolving of issues such as asbestos contamination. The contamination was removed at Eastleigh and the unit was transferred by rail to the East Anglian Railway Museum at Chappel overnight 28/29-06-2011 for display as an exhibit, under a 4-year loan agreement. See also *Class 506 EMUs - similar to the Class 306 EMUs, but built for the Manchester-Sheffield-Wath electric railway References Sources * * Further reading * External links * The Railway Centre 306